# CVE-2026-61554: emp3r0r has an unauthenticated HTTP Polling DoS

> Unauthenticated attackers can create arbitrary polling sessions in emp3r0r C2 servers, consuming resources and causing denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 16 Sep 2026
- **Also known as:** GHSA-4595-rvpx-4q34, GO-2026-6487

## What is CVE-2026-61554?

CVE-2026-61554 is a high-severity denial of service vulnerability in jm33-m0 emp3r0r, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-61554?

3 open source packages ship an affected version, including github.com/jm33-m0/emp3r0r/core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/jm33-m0/emp3r0r/core` | Go | All versions | 0.0.0-20260531142011-aed3d81641ab |
| `github.com/jm33-m0/emp3r0r/core` | Go | All versions | 0.0.0-20260531142011-aed3d81641ab |
| `github.com/jm33-m0/emp3r0r/core` | Go | All versions | 0.0.0-20260531142011-aed3d81641ab |

## How do I fix CVE-2026-61554?

Upgrade github.com/jm33-m0/emp3r0r/core to 0.0.0-20260531142011-aed3d81641ab or later.

## Is CVE-2026-61554 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61554 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61554 and fix it if it is affected.

What it is: CVE-2026-61554 is a high-severity denial of service vulnerability in jm33-m0 emp3r0r, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61554 exists.

Affected packages and fixed versions:
- github.com/jm33-m0/emp3r0r/core (Go): affected all versions; fixed in 0.0.0-20260531142011-aed3d81641ab
- github.com/jm33-m0/emp3r0r/core (Go): affected all versions; fixed in 0.0.0-20260531142011-aed3d81641ab
- github.com/jm33-m0/emp3r0r/core (Go): affected all versions; fixed in 0.0.0-20260531142011-aed3d81641ab

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-61554/ (Markdown: https://insights.sbomify.com/CVE-2026-61554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61554
- OSV: https://osv.dev/vulnerability/CVE-2026-61554

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61554/
Summaries are generated and may contain mistakes; the official description above is the record.